In The News

Calcium and Multivitamins Dominate US Supplement Market

Vitamin D Combats Cancer

Flavonoids May Help Treat Alzheimer's Disease

Grapefruit Compound Inhibits Hepatitis C Virus

Calcium and Multivitamins Dominate US Supplement Market

Calcium was the most-popular singular dietary supplement product sold in the United States in 2006 (the latest available year of comprehensive figures), followed closely by glucosamine sulfate, according to market data recently collected by the research firms Euromonitor, Datamonitor, and Mintel and the trade publication Nutrition Business Journal. The data were presented by Capsugel, a supplement producer, at the May 2008 Supply Side East trade show in Secaucus, New Jersey.

Calcium sales in 2006 topped $1 billion. Glucosamine had sales of more than $800 million. Other best-selling singular dietary supplements were fish oil ($400 million), Co-enzyme Q10 (just under $400 million), probiotics (about $300 million), and noni (Morinda citrifolia, commonly known as Indian mulberry or beach mulberry—with sales of more than $200 million). Other popular supplements included garlic (Allium sativum), Echinacea purpurea, Ginkgo biloba, and S-adenosyl-methionine (SAM-e).

On the vitamin front, multivitamins were by far the most-popular products, accounting for around 60% of the total vitamin market and raking in $4 billion in sales—thus, the top-selling supplement of all supplements sold. Industry leaders predict that sales of multivitamins will grow by 7.5% in constant value between 2003 and 2008.

Trailing multivitamins in sales were B vitamins, with a market worth $1 billion in 2006.  Vitamin C came next, with more than $500 million in sales; followed by vitamins E, D, and A, all with sales under $500 million.

For their part, mineral sales topped more than $750 million.

The aging US population was a major force behind supplement sales, as nearly half of all dietary supplements sold in this country are bought by baby boomers to treat age-related conditions.

Vitamin D Combats Cancer

Two new vitamin D studies add to a growing body of science supporting the potential anti-cancer benefits of the vitamin.

The first study, published in the June 15 issue of the International Journal of Cancer, suggests that the benefits of vitamin D for treating prostate cancer may be due to the action of the vitamin on a specific gene. Researchers from the University of Rochester Medical Center report that the active form of vitamin D in the body, 1,25-hydroxylvitamin D3—1,25(OH)2D—may link with a gene known as G6PD, which releases an antioxidant enzyme and protects DNA from damage. Essentially, these findings conclude that vitamin D may not only treat prostate cancer, it may also prevent it. 

The second study, published in the May issue of the journal Cancer Epidemiology, Biomarkers & Prevention, suggests that maintaining high levels of vitamin D may protect against cancer in general. The research, based on data collected from 3299 patients participating in the Ludwigshafen Risk and Cardiovascular Health study in Germany, found that fatal cancer was reduced by 55% in people with higher vitamin D levels.

Both studies increase the volume of calls for raising the recommended daily allowance of vitamin D from 400 IU to 1000 IU, a change that is currently recommended by the Canadian Cancer Society. These results also highlight the potential of foods fortified with Vitamin D, which may be particularly important in northern climates where sunshine levels are not strong enough for the body to synthesize the vitamin on its own.

Flavonoids May Help Treat Alzheimer's Disease

Flavonoids may help battle Alzheimer's disease, according to a new animal study published in the May 8 online edition of the Journal of Cellular and Molecular Medicine.

In experiments with mice, 2 flavonoids called luteolin and diosmin reduced levels of beta-amyloid, which forms the harmful plaques that build up in the brains of those with Alzheimer's disease. From this phase of the research, investigators would like to use these flavonoids to see if they can reduce amyloid plaque in humans. Flavonoids—which are compounds found in many fruits and vegetables and which have strong antioxidant properties—are safe, with few and very minor reported side effects. If effective, they would thus be significantly less expensive and relatively side-effect free compared to drugs that are currently being developed to reduce amyloid plaque.

In the study, researchers used a mouse model of Alzheimer's disease to test their theory. Using luteolin and diosmin, they were able to reduce the levels of beta-amyloid in the rodents' brains. Furthermore, the researchers found these 2 molecules were targeting a protein called presenilin-1, which has been linked to a genetic cause of Alzheimer's disease. These findings have the potential to change how doctors approach treatment for Alzheimer's patients.

Other experts on Alzheimer's disease urged caution about these findings, citing the need for more study of the effect of flavonoids on a patient's cognitive abilities. For example, the enzyme targeted by the flavonoids, GSK3, has many other important roles in cognitive functioning. Inhibiting that enzyme entirely may lead to neuronal degeneration.

Additionally, promising results in mice studies of the past have led to failures in clinical trials on humans.

Grapefruit Compound Inhibits Hepatitis C Virus

In other news on bioflavonoids, naringenin from grapefruit has been shown to inhibit secretion of cells infected with the Hepatitis C virus (HCV) and could offer a new approach for treating the disease, according to a Harvard Medical School study published in the May issue of Hepatology.

About 3% of the global population is infected with HCV, which can lead to cirrhosis and liver cancer. The current standard therapy of intramuscular injections of interferon and ribavirin is only effective in about 50% of cases and can cause major side effects like leukopenia (interferon) and hemolytic anemia (ribavirin).

Recent research has suggested that HCV may adhere to the lipoprotein life cycle and that compounds and dietary supplements influencing lipoprotein metabolism may also affect HCV.

Such was the case in this new study, in which researchers demonstrated that HCV is actively secreted by infected cells while bound to a very low-density lipoprotein. They then tested the grapefruit flavonoid naringenin and found it reduced HCV secretion in infected cells by 80%. Although the concept of simply supplementing patients’ diet seems appealing, researchers caution that the intestinal wall doesn't absorb naringenin well, which means therapeutic doses of the flavonoid would have to be given by injection or combined with other compounds to boost its absorption by the intestines.

Furthermore, the researchers also noted that naringenin and several other compounds in grapefruit have significant drug-drug interactions that would require future study.